Patellar metastasis from lung adenocarcinoma revealed by FDG PET/CT

We report a case of a 57-year-old woman with lung adenocarcinoma, who presented with right knee pain, swelling, and erythema. The initial [18F]-2-fluorodeoxyglucose positron emission tomography/computed tomography (FDG PET/CT) scan performed for staging purposes showed a right patellar metastasis, subsequently confirmed by pathology. After administration of systemic chemotherapy supplemented by local radiation therapy to the right patella, a follow-up FDG PET/CT scan revealed a grossly stable right patellar lesion. The patient underwent right patellectomy with reconstruction of the extensor mechanism. A subsequent FDG PET/CT scan showed postoperative changes, with no evidence of residual malignancy in the right knee region.